The present invention relates generally to tile cutters and, more particularly, to a tile cutter having one end of a lever arm operatively connected to a sliding carriage at a point below the guide rails supporting the carriage; and the carriage supports the one end of the lever arm at different elevations so that the height of a tile scoring tool may be adjusted to different tile thicknesses.
With a conventional manual tile cutter, a cutting or scoring tool is operatively connected to a handle which slides along a guide bar so that the cutting tool or cutting wheel is moved across the tile surface along a line defining where the tile is to be cut or broken. The cutting tool cuts into the surface of the tile along the desired line, thereby providing a shallow groove or score line in the tile surface. The base has a longitudinally generally centrally spaced breaker bar or edge thereon on which the tile rests. Resilient pads also support the tile on either side of the breaker bar. After the tile is scored, the manual lever arm is manipulated to place pressure pads or plates against the surface of the tile on both sides of the scored line, which is located directly over the breaker bar. As downward pressure is applied to the handle, the pressure plates apply downward forces on the top surface of the tile on both sides of the breaker bar. Continued application of the force is effective to cause the tile to break into two pieces, preferably at a location defined by the score line or groove.
Conventional manual tile cutters are of two general constructions. A first construction is shown in the Ishii U.S. Pat. No. 5,303,690. With that construction, one or more guide bars are supported a predetermined distance above a base which has a centrally located longitudinal breaker bar for supporting the tile. A slider or carriage is slidably mounted to the guide bar(s), and a manually operated lever is pivotally attached to the slider at a point above the guide bar(s). The scoring wheel is pivotally attached to the slider at a point below the guide bar(s), and intermediate linkage is connected between the manually operated lever and the scoring wheel link. The lever is moved to locate the scoring wheel on the tile surface and subsequently locate the pressure plates upon the upper tile surface in order to apply pressure and break the tile over the breaker bar. Such a compound lever construction has the disadvantage of being relatively complex and expensive to manufacture and requires various and numerous pivot pins and pivot joints in order to provide the necessary scoring and breaking action.
A second general construction for a manual tile cutter is illustrated in the Yasuga U.S. Pat. No. 4,026,262. The tile cutter in Yasuga '262 patent is simplified by slidably mounting the manually operated lever directly to a single rail. While that construction is simpler and less expensive to manufacture, it is important that the tile cutter scribe a scoring line that is straight, and that the mechanism be sufficiently rigid to allow the scoring wheel to be placed in the same location and repeatedly track over the same scoring line. The construction of the Yasuga' 262 patent is typically not as rigid or stiff as a construction utilizing a separate carriage on one or more guide bars. Therefore, the construction has the disadvantage of being less able to score the desired straight line in the first instance and repeatedly score over the same line.
The tile cutter of Yasuga '262 patent has a scoring wheel rotatably connected to the end of a pivot arm which is pressed against an elliptical cam. By rotating the elliptical cam, the scoring wheel is moved to different heights relative to the base, thereby accommodating different tile thicknesses. The tile cutter construction of the Yasuga '262 patent has a disadvantage in that the forces applied to the scoring wheel during the scoring process are in turn applied to the elliptical cam at a point offset from the center of the cam. Further, those forces will have a tendency to rotate the cam and change the cutter height unless the cam is very firmly locked into its rotational position.